Continuity mistake: When Jerry runs onto the record player, he runs next to a button panel and there are four buttons on it: Fast, Stop, Start and Change. But when he is pressing random buttons later on in the cartoon, a "Record" button has been added and the "Change" button has disappeared.
Continuity mistake: When Bugs hides in the hole from Elmer, he puts the cow skull over the hole. Elmer then takes away the skull and then puts his head in the hole. At this point, you can see that the background is a desert, but when Elmer takes his head out of the hole, it has changed to a cliff. The background goes back to a desert when Bugs appears in the next shot.
Continuity mistake: When Daffy sees Dr Jerkyl's house, he is holding a telegram in his hand that disappears when we see him in the next shot.
Continuity mistake: When Elmer opens the door and finds Bugs at the dressing table in ladies' underwear, you can see the door is positioned on the left hand side of the frame. But when we see Bugs, the door is now on the right hand side.
Continuity mistake: Near the end, as a plane is getting ready to run down the airstrip, Bogie knocks the gunman out, then uses the gun to shoot the plane in its tracks. When the machine gun starts to fire, it has a long strip of bullets, then fewer, and so on.
Continuity mistake: When we see Elmer reading his book at the beginning of the cartoon, the strap of his gun switches shoulders between shots.
Continuity mistake: Bela Lugosi offers John Berkes a cigar ("a real Havana"), but when he's relaxing, he calls him by his 'street' name, Fingers. The man nervously brings a hand to his collar, but at the cut Fingers' fingers are gone out of frame. (00:06:30)